Well, since you volunteered. As I understand, Atheism not merely lack of belief in a God but a belief that there is no God and no analogous being exists (if I am wrong here, please correct me).
What I'd be curious to hear is exactly what evidence you have that God doesn't exist? The lack of evidence for the existence of God, or a God, or anything really, is enough to propel one to Agnosticism, which is the assertion that one doesn't know. However, Atheism is the assertion that you know that God doesn't exist, and that requires evidence (at least from a logical/scientific viewpoint, which most Atheists I am aware of tend to claim to ascribe to).
Or do you ascribe to this belief in non-existence dogmatically? That is to say, you don't believe in God in the same irrational way that others believe in God? (Using irrational to mean lacking a logical reason rather than as an insult). In that case, you don't believe in nothing, you believe in a manner exactly the same as religions, only in something wholly different.
I'd also be curious as to what you'd tell people who feel enlightenment, or close to God, or whatever their equivalent is, they are feeling? Just some strange reaction of the brain?
By the way, the idea that atheism is the antithesis of morality is a holdover, or a reality in certain areas, from the times when there was no division between religious and secular. Without this division, the rejection of religion became the wholesale rejection of society and many of its rules. In a secular society, rejecting religion simply does not lead to the same amount of disengagement, but in one that isn't secular rejecting religion would be like someone arguing that every single institution of society, political, moral, and otherwise should be abolished. It is much easier to see why this person would be rejected and villainized. It's also a convenient "Us vs Them" with one side saying, "They're religious nuts over there!" and the other going "They're immoral and impious!" for certain parties who shall remain unnamed.
As to those who don't understand why Atheists exist... there are people like that everywhere, who don't understand why anyone believes anything differently from them. They also tend to be the sort who can't understand why those stupid people over there don't just bow to their beliefs. I've met Atheists who portray their beliefs that way, as well as those who are religious, and many who have a similar attitude in some secular affair.